The present invention relates to a method and an apparatus for determining surface configuration utilizing a moving light source and the object self-shadowing created by the motion of the light source across the surface.
Various methods for determinnng the surface topography of an object, or a portion thereof, based on the reflective properties of the subject surface are known in the art. However, these methods suffer a great defect in that either there must be direct contact or the material composition of the surface must be known before the methods can be applied. These latter known methods employ principles of gradual shading by measuring the amount of light reflected back from the surface and, therefore, have a further deficiency in that the surface must be as smooth as possible in order to optimize the reflection therefrom.
The present invention overcomes these deficiencies by providing a means for determining surface configuration without knowledge of the composition of the object or the surface reflective properties thereof, and without any direct contact. The surface information is extracted solely on the basis of object self-shadowing under a moving light source. This property lends the present invention to many applications including, for example, industrial robots, robotic vision, reconnaissance, part inspection, and identification.
The present invention has a further advantage in that the placement of the light source is not critical inasmuch as it may be close to the object or a great distance therefrom.